`XDG_CONFIG_HOME` and `XDG_DATA_HOME` cannot be recongnize correcly by `core.helper`

[yqwu905]

Neovim support specify data and config dir by setting env XDG_CONFIG_HOME and XDG_DATA_HOME, but cosynvim seem don't support that. I believe this's cause by core.helper only check for XDG_CONFIG_DIR and XDG_DATA_DIR.
Maybe you can use vim.fn.stdpath('config') and vim.fn.stdpath('data') instead of manully check env variables and find the config dir? This can ensure the consistency of behavior with neovim.

[glepnir]

this is work for my cli it's outside of neovim.